This application relates to the art of ball retainers for use in ball bearing assemblies, and particularly to ball bearing retainers of a one-piece molded plastic type which snap onto the balls. The ball retainer of the present invention is particularly useful in ball bearings of the maximum capacity-type in which the balls are spaced closely together.
One-piece molded plastic ball retainers of known types include those described in U.S. Pat. No. 3,157,443 issued Nov. 17, 1964, to Draudt; U.S. Pat. No. 3,749,461 issued July 31, 1973 to Liss et al.; and U.S. Pat. No. 3,788,714 issued Jan. 29, 1974, to Degioia et al. Such retainers include outwardly projecting yieldable opposed fingers at the entrance opening of each ball receiving pocket.
In maximum capacity-type of ball bearings, the balls are positioned very close together and the common wall between adjacent ball receiving pockets must be relatively thin. In ball retainers for such bearings, opposed fingers at each pocket entrance opening would have to be extremely thin in order to allow simultaneous outward deformation of such fingers for snapping the retainer onto the balls. Fingers of relatively great thickness are not possible because there is insufficient width of plastic material in the common walls between adjacent pockets to permit simultaneous deformation of the fingers. Making the fingers extremely thin increases the likelihood that they will break and also reduces their holding capacity so they may be incapable of gripping balls with sufficient force to hold the retainer in position.
Previous retainers of the type described also have very large masses of plastic material in the common walls between adjacent pockets, and this inhibits uniform cooling of the plastic material and promotes warpage so that relatively close tolerances are difficult to maintain.